KR20180047074A - Touch panel using humidity sensor and display device comprising the same - Google Patents

Abstract

The present invention relates to a touch panel including capacitive humidity sensors and a display device including the same. More specifically, the touch panel including the humidity sensors includes: a substrate; a lower electrode layer formed in a predetermined area on the substrate; a humidity sensing layer which is made of a polymer patterned on the upper part of the lower electrode layer; and an upper electrode layer formed on the upper part of the humidity sensing layer. The humidity sensing layer is formed by spin-coating a polyimide-based material and heat-treating the spin-coated polyimide-based material to cure the polymer and executing an etching process using a mask pattern to pattern the polymer. The mask is manufactured by using a photosensitive liquid in case of the etching process using the mask pattern. A vacuum in a predetermined chamber is set at 400-500 mTorr while having the power of 600-900W and a substrate temperature in the range of 70-90°C to execute a plasma etching process with CF_4 < O_2 gas. Then, ultrasonic waves and acetone can be used to remove the residual impurities after the etching process.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch panel and a display device using a humidity sensor,

The present invention relates to a touch panel and a display device using a humidity sensor.

Humidity has an important role as an environmental factor in industry as well as in everyday life. It is also a field that demands humidity control in various industries such as automobile, medical equipment, agriculture, semiconductor industry, materials industry, meteorology, HVAC, It is growing rapidly. Each industry requires high sensitivity to humidity measurements, low hysteresis, long stability, and high accuracy.

In this regard, humidity sensors, which are widely used today, utilize changes in capacitance or material resistance. Among them, the capacitance type humidity sensor is made of a dielectric material whose dielectric constant changes when moisture is absorbed. The capacitive humidity sensor is superior to the resistance type humidity sensor in terms of long-term reliability, and is advantageous in that the sensor characteristic is linear and hardly influenced by temperature.

The capacitive humidity sensor, which is currently in commercial use, has a parallel plate type structure. A capacitance type humidity sensor having a parallel plate structure includes an upper electrode, a lower electrode, and a humidity layer sandwiched between the upper electrode and the lower electrode. At this time, moisture is absorbed into the sensing layer through the porous upper electrode, so that the capacitance type humidity sensor measures the humidity. That is, when moisture is adsorbed in the moisture layer, it changes the dielectric constant of the moisture layer and changes the capacitance of the capacitor, thereby sensing the change in humidity.

Therefore, the humidity sensing layer is an important material that affects the performance of the humidity sensor. In the conventional humidity sensor, the humidity sensing material such as ceramic is mainly used. However, this has a problem that the sensitivity for sensing the humidity is extremely low, And hardness of the humidity sensor have been limited and there has been a problem of limiting the field of use of the humidity sensor.

On the other hand, the touch panel can be classified as follows according to the signal detection method. That is, a resistive type in which a position depressed by a pressure in a state where a direct current voltage is applied is sensed through a change in a current or a voltage value, and a resistive type in which a capacitance coupling is used in a state in which an alternating voltage is applied There is a capacitive type and an electromagnetic type in which a selected position is sensed as a change in voltage while a magnetic field is applied. The capacitive sensing technology is a capacitive sensing effect that senses changes in the capacitance value of the sensor due to its proximity, displacement, humidity, flow rate, and acceleration. The sensor is attached to the surface of the touch panel The sensor senses the change in capacitance value. Such capacitive touch panels are widely used as human interface devices for computer displays, portable devices such as mobile phones and tablets.

Accordingly, the present inventors have completed the present invention by fabricating a capacitive humidity sensor by using a polyimide-based material having excellent dielectric constant and electrostatic capacity as a humidity-sensitive material so as to be applicable to a touch panel, by patterning a polymer by a plasma etching process Respectively.

Accordingly, it is a technical object of the present invention to provide a touch panel including a capacitive humidity sensor.

The present invention also provides a display device including the touch panel.

According to an aspect of the present invention,

In a touch panel including a humidity sensor,

The humidity sensor comprising: a substrate; A lower electrode layer formed on the substrate in a predetermined region; A sensing layer formed of a polymer patterned on the lower electrode layer; And an upper electrode layer formed on the humidity sensing layer,

The humidity layer is formed by forming a polymer by curing a polyimide-based material through spin coating and heat treatment, and then patterning the polymer through an etching process using a mask pattern.

When the etching process using the mask pattern, using a mask produced using the photosensitive liquid, to a power of 400 ~ 500 mTorr, a vacuum within a given chamber with 600 ~ 900W, 70 a substrate temperature of ~ 90 ℃ range of CF ₄ / Plasma etching is performed with an O ₂ gas, and then etch residue is removed using ultrasonic waves and acetone.

In the present invention, the polyimide-based material is prepared by adding a diamine and a dianhydride to a solvent to effect a polymerization reaction. The polyimide-based material is prepared by mixing 5 to 20 parts by weight of a diamine and 100 parts by weight of a dianhydride 10 to 20 parts by weight, and the mixture is polymerized at 10 to 35 ° C for 4 to 8 hours to prepare a solid content of 15 to 20% by weight.

The solvent may be selected from the group consisting of N, N-dimethylacetamide (DMAc), dimethylformamide (DMF) or N-methyl-2-pyrrolidone ), And the diamine is used in combination of two or more of them. Examples of the diamine include p-phenylene diamine (p-PDA), 4,4'-oxydianiline ODA) or 4,4'-methylenedianiline (MDA), and the above dianhydride is used in combination with phthalic anhydride ( PA), pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarbocylic dianhydride (3,3', 4,4'-biphenyltetracarbocylic dianhydride (BPDA)) or 4,4'-oxydiphthalic anhydride (ODPA), or a combination of two or more thereof.

According to another aspect of the present invention, there is provided a display device including the touch panel.

According to the present invention, by controlling the surface roughness of the polymer by controlling the etching process of the polymer as the moisture-sensitive material, a humidity sensor capable of improving the adhesion to the upper electrode and increasing the sensitivity area of the humidity sensor Thereby being usefully applied to a touch panel and a display device.

Fig. 1 shows a photograph (left: x100, right: x500) after covering a polymer with a photosensitive liquid in one embodiment of the present invention.
FIG. 2 shows SEM results after covering the polymer with a photosensitive liquid and performing an etching process in one embodiment of the present invention.
3 is a photograph (left: x100, right: x500) after covering the polymer with metal Cr in one embodiment of the present invention.
FIG. 4 shows SEM results after covering the polymer with metal Cr and performing an etching process in one embodiment of the present invention.
5 shows AFM measurement results of the surface morphology of the polymer layer according to the BMR operation output in one embodiment of the present invention.
6 shows AFM measurement results of the surface morphology of the polymer layer with pressure in one embodiment of the present invention.
FIG. 7 shows AFM measurement results of the surface morphology of a polymer layer according to CF ₄ / O ₂ in an embodiment of the present invention.
Figure 8 shows the XPS emission spectra of the polymer coating and etched polymer in one embodiment of the present invention.
Figure 9 shows the TiO2 foreign material remaining on the wafer surface after polymer etching in one embodiment of the present invention.
FIG. 10 shows a state where residual foreign matters are removed according to a method of removing residual foreign matter TiO ₂ in an embodiment of the present invention.
11 is a view showing a manufacturing process of a humidity sensor according to one embodiment of the present invention, wherein (1) is a schematic representation of a manufacturing process of a humidity sensor, (2) is a sectional view of a humidity sensor according to a manufacturing process (3): shows the patterning diagram used in the polymer etching process.
12 is a photograph of a surface of a wafer taken during a manufacturing process of a humidity sensor according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to a capacitance type touch panel including a capacitance type humidity sensor formed by laminating a substrate, a lower electrode layer, a humidity layer and an upper electrode layer in this order. More specifically, the touch panel of the present invention includes a substrate; A lower electrode layer formed on the substrate in a predetermined region; A sensing layer formed of a polymer patterned on the lower electrode layer; And a capacitive humidity sensor including an upper electrode layer formed on the humidity sensing layer, wherein the sensing layer is formed by curing a polymer through spin coating and heat treatment of a polyimide-based material, And patterning the polymer through the through-holes.

According to an embodiment of the present invention, a lower electrode is deposited on the substrate by using a semiconductor thin film process, and then a moisture sensitive polyimide-based material is coated as a moisture-permeable material to a predetermined thickness using a coating apparatus, To form a humidity layer, and an upper electrode is laminated thereon.

At this time, the substrate may be formed of an insulating layer, and may be formed using any one material selected from glass, aluminum oxide (Al ₂ O ₃ ), and silicon (Si), for example.

The lower electrode layer may be formed by depositing and patterning a metal film such as Al, Pt, Ti, or Au. The lower electrode layer may have a single metal film thickness of 100 nm to 300 nm As shown in Fig. In this case, the lower electrode layer may be formed using a semiconductor thin film process so as to facilitate adsorption or desorption of moisture, and process conditions that can optimize the formation of the porous thin film may be applied. Particularly, when the lower electrode layer is formed as a porous thin film layer, the moisture absorbing layer and the atmospheric moisture can be smoothly adsorbed or desorbed, so that the moisture absorbing layer can react sensitively and promptly according to the humidity change. In addition, a mask can be used to have a plurality of holes having various shapes such as a square, a circle, or a triangle, and a semiconductor photolithography process can be used, thereby obtaining a capacitive humidity sensor having excellent sensitivity and response characteristics . Specifically, the lower electrode layer can be controlled to have a power of 2 to 4 kW, a pressure of 1 to 10 mTorr, and a substrate temperature of 120 to 150 ° C so that a porous thin film can be easily formed when a material for forming an electrode is deposited by an e-beam deposition method have.

The upper electrode layer may be formed by depositing and patterning a metal layer such as Al, Pt, Ti, or Au in the same manner as the lower electrode layer.

The upper electrode layer may be formed by depositing graphene. The absorption of water molecules by graphene controls its gaps. Graphene is electrically conductive and sensitive to humidity, and the presence of water molecules in graphene can make it semiconducting by increasing its gap. The top electrode may comprise a layer of graphene formed from several stacked atomic sub-layers. The layer of graphene may have a thickness between, for example, 100 nm and 5 [mu] m.

In order to prevent absorption of moisture from the front surface or the side surface of the lower electrode layer and to improve the characteristics in forming the humidity sensing layer in the lower electrode layer, the moisture sensing layer is patterned to be larger than the area of the lower electrode layer desirable.

At this time, the humidity sensing layer is formed of a polyimide-based material sensitive to moisture, and a polymer is cured by spin coating and heat treatment of a polyimide-based material on the upper surface of the lower electrode, and then the polymer is etched using a mask pattern Patterning will form the polymer layer.

Since the polyimide does not substantially dissolve in the solvent, the polyimide precursor in the form of a solution is generally subjected to a processing step, followed by imidization by heat, and the solvent is removed by heat treatment to completely imidize the polyimide precursor. That is, the polyimide precursor can be thermally treated to form a polyimide layer to form a moisture-sensitive layer. Specifically, in order to completely imidize the polyimide precursor, the polyimide precursor is heat-treated at a temperature of 50 to 250 ° C. for 30 to 100 minutes in a vacuum atmosphere desirable.

At this time, the polyimide precursor is prepared by adding a dianhydride and a diamine to a solvent and performing a polymerization reaction. Specifically, an aromatic dianhydride and an aromatic diamine are reacted in a polar solvent. First, a diamine Is dissolved in a solvent and then reacted with a dianhydride to prepare a polyimide (polyamic acid) precursor, and upon formation of the humidity layer, heat is applied to the water to form a cyclized polyimide to produce a humidity layer . This is because the processability and moldability of the aromatic polyimide are poor when the polyimide precursor is passed through.

More specifically, first, 5 to 20 parts by weight of diamine is dissolved in a solvent, and 10 to 20 parts by weight of dianhydride is added to 100 parts by weight of the solvent. The mixture is slowly reacted at 10 to 35 ° C for 4 to 8 hours to obtain a solid content A polyimide precursor in the form of a solution in an amount of 15 to 20% by weight can be prepared, and if the polymerization conditions are out of the above range, the polyimide precursor may not be produced properly. In this case, the solvent is a solvent in which N, N-dimethylacetamide (DMAc), or N, N-dimethylacetamide (DMAc), which catalyzes the polymerization reaction during polymerization and then facilitates imidization in the imidization process, N-methyl-2-pyrrolidone (NMP)) is used alone or in combination of two or more thereof, and the diamine is used in combination with paraphenylenediamine (p-PDA), 4,4'-oxydianiline (ODA), or 4,4'-methylenedianiline (MDA) ), And the above dianhydrides are used in combination of phthalic anhydride (PA), pyromellitic dianhydride (PMDA), 3,3 ' , 4,4'-biphenyltetracarbocylic dianhydride (BPDA), or 4,4'-oxydipthalic acid dianhydride Among fluoride (4,4'-oxydiphthalic anhydride (ODPA)) may be used either alone or in combination of two or more.

In the polymer etching for patterning the polymer, since the polyimide contains a small amount of solid content and bubbles, the polyimide precursor which has been sufficiently shaken and left to be applied is applied to the upper surface of the substrate on which the lower electrode is laminated using a spin coater, And then the etching process is performed using a mask.

Therefore, in the embodiment of the present invention, by controlling the etching process to protect the polymer as the moisture-sensitive material and effectively forming the etched and patterned polymer layer, it is possible to improve the contact area with the humidity of the humidity sensor, And the sensitivity of the test results can be increased.

Specifically, in the present invention, the mask used in the polymer etching is preferably a mask made of a photosensitive liquid. In this case, the etching rate of the photosensitive liquid is faster than the etching rate of the polymer, so that the coating thickness of the photosensitive liquid is 3 to 5 times the thickness of the polymer coating. This is to protect the polymer in the etching process and facilitate the removal of the photosensitive liquid after the etching process.

Further, during the plasma etching using the mask made of the photosensitive liquid, if the surface roughness is excessively high due to etching, the adhesion with the upper electrode is lowered, and when the surface roughness is low, the surface area for sensing the humidity is reduced, Is 10 to 20 nm, the sensitivity of the humidity sensor can be improved by increasing the surface area for sensing the humidity while improving the adhesion with the upper electrode.

In this case, as the power is increased, the etching speed is improved. However, when the power is excessively high, damage to the photosensitive liquid protecting the polymer is caused. Therefore, it is required to provide an appropriate power. Preferably, the etching power is 600 to 900 W, .

Also, when the pressure is increased, the etching rate increases with the increase of the etching gas in the chamber, and then the etching rate decreases after a certain pressure. Accordingly, when the etching process is performed at a pressure of 400 to 500 mTorr, more preferably 450 mTorr, the surface is formed with a surface roughness of 19.26 nm, thereby improving the adhesion to the upper electrode, It is possible to increase the sensitivity of the humidity sensor by maximizing the sensing surface area.

In addition, an etching gas of CF ₄ / O in accordance with the mixing ratio of the _two gases, according to the bar, the embodiment of the present invention that the etching rate varies CF _4: of the polymer etch rate to the 9 conditions the fastest, O _2: O ₂ = 1 It was confirmed that the etching rate was gradually decreased with the increase of O ₂ , and the etching was not performed under the condition of CF ₄ : O ₂ = 1: 1, and it was confirmed that the surface roughness was increased with the increase of O ₂ and decreased again 3 and FIG. 7), which means that the more fluorine ions participate in the reaction, the less volatile reaction products such as TiF _x and (CF _n ⁺ ) _m , which are scattered on the etched surface, are formed and the etching surface becomes rougher. That is, in the etching process, the split metal mask material and the plasma polymer residue form an uneven etching surface, which is dispersed in the etching region and forms a microscopic auxiliary mask, and the auxiliary mask is removed by the O ₂ plasma, It is possible to control the etching process by controlling the mixing ratio of the CF ₄ / O ₂ gas. Therefore, it is preferable that the mixing ratio of CF ₄ / O ₂ gas is 1: 9 in order to improve the etching rate while having an appropriate surface roughness.

In the touch panel according to the present invention, the capacitive humidity sensor is attached to the surface, and the sensor senses a change in capacitance value. The humidity sensor operates by applying a voltage to both ends of the upper and lower electrode layers, The capacity value is determined by the inherent dielectric constant of the upper electrode layer / the lower electrode layer, and when the moisture particles are introduced into or discharged from the humidity sensing layer by the external humidity change, the capacitance value is changed by the change of the dielectric constant of the sensing layer by moisture, A change in the current value induced in the capacitor is generated, and it can be said that the change in the capacitance value is reversely converted to the humidity.

The display device including the touch panel of the present invention may be a smart phone, a tablet personal computer, a mobile phone, a video phone, an e-book reader, a desktop PC a laptop personal computer, a netbook computer, a personal digital assistant (PDA), a portable multimedia player (PMP), an MP3 player, a mobile medical device, a camera, or a wearable device wearable device (e.g., a head-mounted-device (HMD) such as electronic glasses, an electronic garment, an electronic bracelet, an electronic necklace, an electronic app apparel, an electronic tattoo, or a smartwatch) can do. In another embodiment, the display device may be a smart home appliance. [0003] Smart household appliances, such as electronic devices, are widely used in the fields of television, digital video disk (DVD) player, audio, refrigerator, air conditioner, vacuum cleaner, oven, microwave oven, washing machine, air cleaner, set- Boxes, game consoles, electronic dictionaries, electronic keys, camcorders, or electronic frames. It should also be apparent to those skilled in the art that the electronic device according to various embodiments of the present invention is not limited to the devices described above.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited by the following examples.

&Lt; Example 1 >

First, 5 parts by weight of p-phenylene diamine (p-PDA) was dissolved in 100 parts by weight of N-methyl-2-pyrrolidone (NMP) , 10 parts by weight of 3,3 ', 4,4'-biphenyltetracarbocylic dianhydride (BPDA) (3,3', 4,4'-biphenyltetracarbocylic dianhydride (BPDA)) was added and the mixture was gradually added To prepare a polyimide precursor in the form of a solution having a solid content of 15% by weight.

The polymer was applied to the surface of the wafer with a spin coater at a thickness of 2.5 mu m and then heat treated at a temperature of 210 DEG C for 10 minutes at 100 DEG C for 30 minutes to solidify the liquid polymer. After curing and drying by the heat treatment, the thickness decreased to 1.8 탆.

In addition, a small number of pinholes may be formed on the surface of the wafer due to the presence of a small amount of solid particles and bubbles in the polymer when the polymer is applied. Therefore, to prevent pinhole formation, the polymer must be sufficiently shaken and allowed to stand before application of the polymer.

Next, a mask for etching was fabricated using a photosensitive liquid and metal (Cr), and a polymer etching test was performed using a BMR etching facility.

FIGS. 1 and 2 show the etching mask test results produced using the photosensitive liquid, and FIGS. 3 and 4 show the etching mask test results produced using Cr. 1 is a photograph (left: x100, right: x500) after covering with a photosensitive liquid, Fig. 4 shows a SEM photograph. The results are shown. The results are shown. It was found that the etch rate of the photosensitive liquid was slightly faster than that of Cr, and it was determined that the thickness of the photosensitive liquid should be thicker than the thickness of the polymer. In this embodiment, the thickness of the photosensitive liquid is 6 um, It was confirmed that the sensitizing solution has a sufficient protective role in the polymer etching process. On the other hand, in the case of etching a mask made of metal, it can be seen that a distortion occurs around the periphery after etching (FIG. 4) because the thickness of the metal is thinner. From this, it is considered that the protective effect of the photoresist solution which is economical and simple in process is superior to the metal although it serves as a sufficient protection in the etching process.

&Lt; Example 2 >

From the results of Example 1, the etching rate according to the BMR output, the pressure in the chamber, and the mixing ratio of the CF ₄ / O ₂ gas was tested using a mask made of a photosensitive liquid.

The results are shown in Tables 1 to 3 and 5 to 7 below.

Psalter BMR power (W) Temperature
(° C) CF ₄
(sccm) O ₂
(sccm) pressure
(mTorr) time
(min) Etching rate
(nm / min) One 300 81 10 70 450 4 42.5 2 600 81 10 70 450 4 300 3 900 81 10 70 450 4 425

Table 1 shows the polymer etching rate according to BMR operation output conditions. As a result, it can be seen that as the work output is higher, the etching rate is increased to 42.5, 300, and 425 nm / min. Therefore, the higher the work output, the higher the etch rate. However, when the work output is higher than 900 W, it may cause a large damage to the photosensitive liquid during the etching operation.

5 shows the result of measurement of the surface morphology of the polymer layer by AFM (atomic force microscopy). Referring to FIG. 5, the surface roughness of the polymer increases from 10.25 nm to 19.26 nm as the working output increases.

Psalter BMR power (W) Temperature
(° C) CF ₄
(sccm) O ₂
(sccm) pressure
(mTorr) time
(min) Etching rate
(nm / min) 4 900 81 10 70 300 4 235 5 900 81 10 70 450 4 425 6 900 81 10 70 600 4 385

Table 2 shows the polymer etching rate with pressure. As a result, it can be seen that when the pressure is increased from 300 mTorr to 450 mTorr, the etching rate is increased to 235 and 425 nm / min, and then increased to 600 mTorr to 385 nm / min.

6 shows the result of AFM (atomic force microscopy) measurement of the surface morphology of the polymer layer depending on the pressure when the BMR working output is 900 W and CF ₄ / O ₂ = 8 sccm / 72 sccm. , The surface morphology of the polymer changes non-monotonically and exhibits a minimum roughness at a pressure of 450 mTorr. The highest roughness appears at a pressure of 600 mTorr. Therefore, it can be confirmed that the roughness can be controlled by the pressure.

Psalter BMR power (W) Temperature
(° C) CF ₄
(sccm) O ₂
(sccm) pressure
(mTorr) time
(min) Etching rate
(nm / min) 7 900 81 0 80 450 3 53 8 900 81 8 72 450 3 795 9 900 81 16 64 450 3 410 10 900 81 24 56 450 3 200 11 900 81 36 48 450 3 30 12 900 81 40 40 450 3 0 13 900 81 48 36 450 3 0 14 900 81 56 24 450 3 0 15 900 81 64 16 450 3 0 16 900 81 72 8 450 3 0 17 900 81 80 0 450 3 0

Table 3 shows the polymer etching rate according to the mixing ratio of CF ₄ / O ₂ gas as the etching gas. As a result, it can be confirmed that the polymer etching rate is the fastest at the condition of CF ₄ : O ₂ = 1: 9 and the maximum value can reach the level of 795 nm / min and satisfies the process requirements. When the amount of O ₂ as the reactive gas is lower than 50% (Specimens 12 to 17), the reaction does not occur and the etching rate is 0.

7 also shows that when the BMR working output is 900 W, the pressure is 450 mTorr, and the CF ₄ / O ₂ gas flow rates are 0/80, 8/72, 16/64, 24/56 and 32/48 sccm, respectively, (Atomic force microscopy) of the surface morphology. As a result, the surface morphology of the polymer was found to vary from 9.56 nm to 19.26 nm and to 22.89 nm as the amount of O ₂ increased (0/80, 8/72, 16/64 sccm). The main reason for the increase of the surface roughness is thought to be the generation of low volatility reaction products such as TiF _x and (CF _n ⁺ ) _m , scattered on the etching surface by the auxiliary mask. That is, the more fluorine ions participate in the reaction, the more the product is formed and the etched surface becomes rougher. It can also be seen that the surface morphology of the polymer improves from 22.89 nm to 18.88 nm, to 17.35 nm, with a continuous increase in the amount of O ₂ (16/64, 24/56, and 32/48 sccm).

The main reason for the non-uniform etched surface from this is the split metal mask material and the plasma polymer residue, which can be dispersed in the etched area and form a microscopic mask, the oxygen plasma created by the addition of O ₂ removes this layer And the surface morphology can be improved.

8 shows XPS (X-ray photoelectron spectroscopy) irradiation spectra of the polymer coating and the etched polymer. This allows analysis of the chemical composition, bonding state and mass / charge of each polymer surface. Specifically, Fig. 8 (a) shows the characteristics of the coated polymer, Fig. 8 (b) shows the characteristics of the etched polymer, and Fig. 8 (c) shows the characteristics of the overetched polymer.

Referring to this, it can be seen that the coated polymer in Figure 8 (a) contains Ti, O, N, and C near the surface, and the spectral intensity peak near 285.0 eV is due to C 1 s Which is used as a reference for correcting the spectral energy. Referring also to Figure 8 (b), there are XPS optoelectronic lines of Ti, C, O, F, and N near the CF ₄ / O ₂ etched polymer surface and the valence type for F (KLL) (838.2 eV) Valence-type Auger lines can be identified. Referring also to Fig. 4 (c), there is an XPS optoelectronic line of Si near the CF ₄ / O ₂ overetched polymer surface, and Ti is left intact.

9 and 10 show the test results of removal of residual foreign matter after polymer etching.

Specifically, FIG. 9 shows a TiO ₂ foreign substance remaining on the surface of the wafer after polymer etching (a: × 1,000, b: × 15,000). As a result, TiO ₂ remained on the surface of the wafer after polymer etching .

10 shows a state where residual foreign matter is removed according to the method of removing residual foreign matter TiO _2. FIG. 10A shows a state where the residual foreign matter is removed by using the deionized water treatment, the acid treatment, the alkali treatment, The foreign object is removed. As a result, it can be confirmed that a large amount of foreign matter still remains in the deionized water treatment, and a small amount of foreign matter remains even in the acid treatment or the alkali treatment. In the case of only the acid treatment, . On the other hand, in the case of using ultrasonic and acetone, not only the foreign matters remain on the polymer surface, but also the photoresist mask on the polymer surface can be removed together.

Production Example 1 Production of humidity sensor

In this production example, a humidity sensor using an etched polymer was prepared.

Fig. 11 (1) is a schematic representation of the manufacturing process of the humidity sensor, and Fig. 11 (2) is a cross-sectional view of the humidity sensor according to the manufacturing process , And Fig. 11 (3) shows the patterning diagram used in the polymer etching process.

Specifically, the method is as follows.

(1) Cleaning

In this process, a silicon chip and a glass substrate were used. First, SiO ₂ was coated on the substrate surface by LPCVD (low pressure chemical vapor deposition) in order to increase the adhesion force after cleaning the substrate surface.

(2) Lower electrode deposition

Ti and Pt (Ti / Pt) were deposited to a thickness of 100 / 200nm using a metal evaporator. Finally, the substrate was cleaned by lift-off equipment So that the desired pattern can be left. FIG. 12 (1) shows a photograph after Ti / Pt deposition.

(3) Polymer and photopolymer coating

11 (2) -a) was applied on the lower electrode at a thickness of about 2 μm by using a spin coater facility, and then a photosensitive liquid was applied to the etching protection layer to a thickness of about 6 μm (FIG. 11 ). Fig. 12 (2) shows a photograph after coating the polymer and the photosensitive liquid.

(4) Polymer etching

The polymer etching operation was performed using BMR etching equipment (Fig. 11 (2) -c). 10% CF ₄ and 90% O ₂ were used as the etching gas, and the process conditions were 900 W of the facility operation output, 81 ° C of temperature, 450 mTorr of pressure, and 5 minutes of time. The pattern for the polymer etching was the pattern shown in Fig. 11 (3). After the etching, ultrasonic waves and acetone were used to remove etch residue (Fig. 11 (2) -d). Fig. 12 (3) shows a photograph after polymer etching with BMR etching equipment.

(5) Top electrode deposition

Ti / Pt / Au metal was deposited to a thickness of 100/100/300 nm in the same manner as the lower electrode deposition method. FIG. 12 (4) is a photograph of Ti / Pt / Au deposited on the upper electrode.

From the results of the examples and the production examples, it was confirmed that the conditions of the polymer etching process for obtaining the surface roughness with efficient etching were confirmed according to the present invention. From this, the capacitance type humidity sensor can be manufactured by polymer etching, It can be confirmed that the invention can be applied to a panel.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are intended to be illustrative, but not limiting, in all respects.

Claims (3)

In a touch panel including a humidity sensor,
The humidity sensor comprising: a substrate; A lower electrode layer formed on the substrate in a predetermined region; A sensing layer formed of a polymer patterned on the lower electrode layer; And an upper electrode layer formed on the humidity sensing layer,
The humidity layer is formed by forming a polymer by curing a polyimide-based material through spin coating and heat treatment, and then patterning the polymer through an etching process using a mask pattern.
When the etching process using the mask pattern, using a mask produced using the photosensitive liquid, to a power of 400 ~ 500 mTorr, a vacuum within a given chamber with 600 ~ 900W, 70 a substrate temperature of ~ 90 ℃ range of CF ₄ / Plasma etching is performed with an O ₂ gas, and ultrasonic waves and acetone are used to remove etching residues. The method according to claim 1,
The polyimide-based material is prepared by adding diamine and dianhydride to a solvent to effect polymerization. The polyimide-based material is prepared by mixing 5 to 20 parts by weight of diamine and 10 to 20 parts by weight of dianhydride And the mixture is polymerized at 10 to 35 ° C for 4 to 8 hours to prepare a solid content of 15 to 20% by weight.
The solvent may be selected from the group consisting of N, N-dimethylacetamide (DMAc), dimethylformamide (DMF) or N-methyl-2-pyrrolidone ), And the diamine is used in combination of two or more of them. Examples of the diamine include p-phenylene diamine (p-PDA), 4,4'-oxydianiline ODA) or 4,4'-methylenedianiline (MDA), and the above dianhydride is used in combination with phthalic anhydride ( PA), pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarbocylic dianhydride (3,3', 4,4'-biphenyltetracarbocylic dianhydride (BPDA)), 4,4'-oxydiphthalic anhydride (ODPA), or a combination of two or more thereof. A display device comprising the touch panel according to claim 1 or 2.

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